Self-cleaning detonation attenuation means for internal combustion engines



A. G. BODINE, JR 2,760,475 SELF-CLEANING DETONATION ATTENUATION MEANS FOR INTERNAL COMBUSTION ENGINES Original Filed July 2, 195] Aug. 28, 1956 INVENTOR. AL 51% 7 @fiOD/M', .JE

flrrokwfx United States Patent SELF-CLEANIN G DETONATION ATTENUATION MEANS FOR INTERNAL COMBUSTION EN- GINES Albert G. Bodine, Jr., Van Nuys, Calif.

Original application July 2, 1951, Serial No. 234,688, now

Patent No. 2,573,536, dated October 30, 1951. Divided and application October 24, 1951, Serial No. 252,818, now Patent No. 2,738,781, dated March 20, 1956. Divided and application December 6, 1955, Serial No. 551,263. Again divided and this application April 16, 1956, Serial No. 578,474

4 Claims. (Cl. 123-191) This invention relates generally to internal combustion engines and to means for suppressing irregular burning and detonation of fuel-air mixture therein. The invention is based on my discovery that detonation in combustion engines involves acoustic phenomena and can be alleviated by means of certain acoustic apparatus used in combination with the combustion chamber.

The present application is a division of my copending application Ser. No. 551,263, filed December 6, 1955, allowed February 15, 1956, entitled Piston Carried Detonation Suppression Means for Internal Combustion Engines. That parent application was in turn a division of my application Ser. No. 252,818, filed October 24, 1951, entitled Engine Detonation Control by Acoustic Methods and Apparatus, now Patent No. 2,738,781, which application was a division of my earlier application Ser. No. 234,688, filed July 2, 1951, entitled Engine Detonation Control by Acoustic Methods and Apparatus, now Patent No. 2,573,536.

The present invention is based on the fact that detonation in an engine combustion chamber produces sound waves, a large part of which rise to high amplitude at resonant frequencies of the chamber, and on my discovery that the sound waves produce the various wellknown and harmful manifestations of detonation. According to my basic invention, I inhibit or attenuate these harmful effects by interfering with or attenuating the high amplitude detonation-induced sound waves, and this is done by use in connection with the combustion chamber of acoustic attenuation means made responsive to the frequencies at which the detonation induced sound waves build up to high amplitudes.

A general object of the invention is the provision of simple and effective acoustic attenuator means for the combustion chamber of an internal combustion engine, with particular reference to substantial efiectiveness, simplicity, low cost, and with inclusion of a self-cleaning feature.

The acoustic attenuation means of the present invention is capable of being used in either the combustion chamber head Wall or the head wall of the piston, though comprising configurations particularly well adapted for incorporation in the head wall of the piston, and the invention will be so illustrated and described hereinafter, but without limitation thereto.

The invention will be best understood by reference immediately to the following detailed description of an illustrative embodiment thereof, in which:

Fig. 1 is a vertical transverse section through an internal combustion engine equipped with the wave attenuator configurations of the invention; and

Fig. 2 is a vertical medial section through the piston of the engine of Fig. 1, showing a plurality of attenuators in vertical medial section.

"ice

In the drawings, there is shown an illustrative L-head engine comprised of a water-cooled block 10, a watercooled head 11 fastened to block 10, a piston 14 working in cylinder 15 in block 10, exhaust valve 16, and spark plug 17. It will be understood that an intake valve (not shown) will be located along-side exhaust valve 16. The block 10 and head 11 are shown with more or less con-- ventional cooling jackets and head 11 has an inner combustion chamber wall 20 enclosing a combustion chamber space 21 over the cylinder and valves, as shown. The head or top wall 26 of the piston is formed with a plurality of bores 26a, in any suitable pattern, extending downwardly from its top surface, and an enlarged counterbore 26b extends upwardly from below. Helmholtz resonator structures, generally designated at 27, include a cylindric base portion 27a mounted in counterbore 26b, and secured in position by peening as at 27b. Extending upwardly from base portion 27a is a reduced cylindric member 28 forming a resonator chamber 29. As shown, the side walls of the cylinder 28 are annularly spaced from the defining walls of bore 26a, and the lower ends of the side walls of cylinder 28 are formed with a series of gas ports 30, which ports constitute the neck of the resonator. Enclosed within chamber 29 is a steel ball 31. The resonator 27 functions in the now known manner to attenuate detonation frequency waves of frequency to which it is resonant. The chamber being exposed to the flame, carbon accumulation therewithin is minimized. In addition the steel ball 31 is free to rattle about inside the chamber owing to the reciprocating motion of the piston, and this rattling ball has a scouring action on the inside surfaces of the chamber, whereby carbon accumulation is prevented.

It will be understood that the drawings and description are merely illustrative of one specific embodiment of the invention, and that various changes in design, structure and arrangement may be made without departing from the spirit and scope of the appended claims.

I claim:

1. For use with an internal combustion engine having a combustion chamber and a cylinder opening into said chamber, a piston adapted for reciprocation in said cylinder, a Helmholtz resonator chamber mounted on the top of said piston and provided with a restricted gas passage opening to said resonator chamber, and a ball loosely placed inside said resonator chamber to prevent carbon accumulating therewithin.

2. The subject matter of claim 1, wherein the Helmholtz resonator comprises a chamber mounted in a recess sunk in the top of the piston, and wherein the gas passage opening to said resonator chamber is located in the inside end region of said recess, and combustion chamber, and a gas passage is provided between the combustion chamber and said passage opening to said resonator chamber.

3. The subject matter of claim 2, wherein the sides of said resonator chamber are spaced from the opposed surfaces of said recess.

4. For use with an internal combustion engine having a combustion chamber and a cylinder opening into said chamber, a piston adapted for reciprocation in said cylinder, a Helmholtz resonator chamber mounted inside a recess sunk into the top of the piston, substantial side surface areas of said resonator chamber being spaced from the opposed surfaces of said recess, and restricted gas passage means opening from the inner end region of the space between said chamber and opposed recess surfaces into the inner end region of said resonator chamber.

No references cited. 

